On/off and modulated/duty-cycled solenoid tester

ABSTRACT

An apparatus for performing on/off or modulated/duty-cycled testing on a solenoid in a computer controlled automatic transmission when the solenoid is removed from the vehicle or while the solenoid is in the vehicle. The apparatus comprises: three jacks, a switch when actuated for performing a diode test, circuitry for electrically connecting the apparatus to the solenoid and preventing over current and over voltage surges, circuitry for performing the on/off testing, circuitry for performing the modulated/duty-cycled test and pneumatic components for supplying air pressure to the solenoid.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for transmission testingand, particularly, to a single testing unit for performing variablevoltage (on/off) or modulated/duty-cycled testing of a solenoid in acomputer controlled automatic transmission.

2. General Background

There are many manufactures of computer controlled automobiletransmissions. Each manufacture's transmission may utilize a differenttype of control signal to the electronic control module (ECM) toactivate one of the several solenoids. Furthermore, the solenoids may beof on/off or modulated/duty-cycled type of operation. Therefore,troubleshooting a solenoid of a computer controlled automatictransmission becomes complicated.

Several devices have been patented which are aimed at transmissiontesting.

U.S. Pat. Nos. 3,273,384 and 3,302,107 are directed to hydraulics andindividual component applications and testing and are not related to thecomputer controlled automatic transmission of today's vehicles.

U.S. Pat. No. 4,854,165 is directed to testing electrical switches thatare responsive to fluid under pressure. Although the invention isdirected to on/off solenoid testing, modulated/duty-cycled testing isnot performed.

U.S. Pat. No. 5,060,177 is directed to testing only a specific Chrysler™transmission by simulating shifting conditions just as the onboardcomputer might do and is very complex in operation.

U.K. Patent Application GB 2 019 585A is directed to reading andchecking electrical circuits within the transmissions of commercialapplications and not to passenger automobiles.

The known testing devices do not address the need for a single unittesting device capable of testing a variable voltage (on/off) ormodulated/duty-cycled solenoid for a computer controlled automatictransmission.

SUMMARY OF THE PRESENT INVENTION

The preferred embodiment of the apparatus of the present inventionsolves the aforementioned problems in a straightforward and simplemanner. What is provided is a single unit designed to perform bothon/off and modulated/duty-cycled testing of a solenoid in a computercontrolled transmission.

In view of the above an object of the invention is to provide anelectrical connection for providing power to the single unit while benchtesting the solenoid when the solenoid is removed from the vehicle orwhen the solenoid is in the vehicle. The electrical connection isadapted for connection to a vehicle's cigarette lighter.

A further object of the invention is to provide a faceplate havingsimple operator controls for selecting the on/off test or themodulated/duty-cycled test, as well as, the testing parameters for themodulated/duty-cycled solenoid.

A further object of the invention is to provide pneumatic components forconnecting any regulated air supply available in most repair shops tothe intake port of the solenoid.

A further object Of the invention is to provide circuitry for performingover current and over voltage protection, circuitry for performing theon/off test and circuitry for performing the modulated/duty-cycled testhaving overheating protection.

In view of the above, the invention is capable of modulated/duty-cycledtesting of U.S. built pressure control variable force solenoids andmodulated converter clutch solenoids and most Asian pressure controlsolenoids. The invention is further capable of on/off testing moston/off solenoids and diodes of the solenoids having a-resistance of 15ohms or higher.

BRIEF DESCRIPTION OF THE DRAWING

For a further understanding of the nature and objects of the presentinvention, reference should be had to the following description taken inconjunction with the accompanying drawing in which like parts are givenlike reference numerals and, wherein:

FIG. 1 illustrates the testing unit housing and faceplate or controlpanel of the preferred embodiment of the apparatus of the presentinvention;

FIG. 2 illustrates the pneumatic circuit of the embodiment of FIG. 1;

FIG. 3 illustrates the power connections, power protection circuitry andthe on/off solenoid testing circuitry of the embodiment of FIG. 1; and,

FIG. 4 illustrates the circuitry for performing themodulated/duty-cycled solenoid testing of the embodiment of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing, and in particular FIG. 1, the apparatus ofthe present invention is designated generally by the numeral 10.Apparatus 10 of FIG. 1 is comprised of a faceplate 15, pneumatic circuit40 (FIG. 2) and suitable housing 16. Disposed within housing 16 iselectronic circuitry 51, 50 and 60 (FIGS. 3 and 4) for performing theon/off or modulated/duty-cycled test on a solenoid.

Faceplate 15 acts as a heat sink for the electrical circuitry of thepresent invention and has thereon an air pressure gauge 11, voltmeter20, light emitting diodes 25 and 30 for providing the visual indicatorsfor the operator of the present invention. In the exemplary embodiment,pressure gauge 11 is a 0 to 60 psi (pounds per square inch) pressureindicator for monitoring the air pressure conditions during testingthereby checking the pneumatic integrity Of the solenoid under test.Voltmeter 20 is a 0 to 5 volt direct current analog meter whichindicates to the user the output voltage to jack 23. Light emittingdiodes 25 and 30 are red light emitting diodes; however, any color orother suitable light source may be used.

Faceplate 15 is further comprised of three input jacks 21, 22 and 23 forelectrically connecting the solenoid to electrical circuitry 50 and 60(FIGS. 3 and 4). Jacks 21 and 22 are used when performing the on/offsolenoid test on an on/off solenoid. Jack 21 is a red push-in connectionused to insert a red electrical lead thereby electrically connecting thetesting device to the positive side of the on/off solenoid. Jack 22 is ablack push-in connection used to insert a black electrical lead therebyelectrically connecting the testing device to ground or the negativeside of the on/off solenoid.

Faceplate 15 is further provided with several operator controls forselecting the testing mode, as well as, testing parameters. Push buttonswitch 26 is provided to perform the variable voltage (on/off) solenoidtest. Push button switch 24 initiates a diode test on an on/off solenoidwhen actuated (switch 26 needs to be deactivated before performing thediode test since it is a momentary switch, not a maintain switch);otherwise, push button switch 24 connects jack 22 to ground. Switch 29turns on the control circuit 60 (FIG. 4) for performing themodulated/duty-cycled test. Selector switch 27 selects a high or lowHertz (frequency) for the duty-cycled test. Potentiometer 28 adjusts thevoltage output to jack 23 and has a 0-5 volt range. Range adjustment 28is used to calibrate apparatus 10 (and, therefore, limits the high endvoltage) since each solenoid is different. Jack 23 is a red push-inconnection used to insert a red electrical lead thereby electricallyconnecting the testing device to the positive side of amodulated/duty-cycled solenoid. Potentiometer 31 controls the duty-cycleoutput during the modulated/duty-cycled test procedure. It has a four(4) volt span: 1-5 volts. When duty cycle 31 is maximized, rangeadjustment 28 is used to set the maximum voltage at 5 volts. In theexemplary embodiment, selector switch 27 is a rotary switch. Switch 29is a push button switch. Push button switch 24 is a conventional doublepole-double throw switch.

The three jacks 21, 22 and 23 in combination with switch 24 allow theapparatus to connect to a solenoid (not shown) for performing one of twosolenoid testing modes whereby various types of manufactured solenoidsare accommodated and a diode test.

FIG. 2 illustrates the pneumatic circuit 40 of the invention 10. Nozzle12 is connected to control valve 13. Nozzle provides connection to theintake port of the solenoid. Control valve 13 controls the air suppliedto nozzle 12 during the testing procedure. Port 14 is a standard malequick disconnect air fitting for connection to the air supply (notshown). Port 14 may be connected to any regulated shop air supply or aseparately supplied manifold. Additional manifolds and clamps arerequired for securing the solenoid when testing a duty-cycled solenoid.Internal manifold 45 connects port 14 to nozzle 12 thereby providing airsupply to nozzle 12 under the control of control valve 13. Pressuregauge 11 monitors the air pressure during testing of the solenoid.

FIG. 3 illustrates circuits 50 and 51 of invention 10. Power plug 55provides a connection to supply power to the electronic circuitry of thepresent invention. Apparatus 10 can be powered electrically by anysuitable twelve volt direct current source capable of delivering atleast five amperes of electrical power. Additionally, in order to test asolenoid in a vehicle, power plug 55 can be adapted to connect to avehicle's cigarette lighter so that it is not necessary to carry a powersource when operating the present invention. Henceforth, the singletesting unit is capable of testing individual computer controlledautomatic transmission solenoids both electrically and pneumaticallyonce they have been removed from the vehicle or while in the vehicle.Power plug 55 is connected to protection circuitry 51 via leads 1 and 2.Lead 1 of power plug 55 is connected to one side of fuse 54 forproviding current overload protection to circuit 50. Lead 2 is connectedto ground and to one side of Zener diode 56 for providing over voltagesurge protection. The other side of fuse 54 is connected to the otherside of Zener diode 56. In the exemplary embodiment, Zener diode 56 is a1.5KE20A diode and fuse 54 is a 5 amp fuse.

For performing the on/off test procedure, circuit 50 is provided with atwo position push button switch 26 which is normally in the openposition (as shown) thereby providing the circuitry with a ground ornegative voltage potential for the external solenoid diode test. Whenswitch 26 is closed, power from the output of protection circuitry 51 issupplied to the solenoid (not shown) during the on/off test via resistorR6 connected to jack 21. One side of resistor R6 is connected to switch26 and the other side is connected to jack 21 and one side of resistorR2. The other side of resistor R2 is connected to the base of transistorQ1. Resistor R3 is connected to said other side of resistor R2 and tothe emitter of transistor Q1. The emitter of transistor Q1 is furtherconnected to ground. In the exemplary embodiment, transistor Q1 is a2N3904 transistor. Resistors R2 and R3 are 4.7K ohm resistors. ResistorR6 is a 8.2 ohm resistor (10 watt ww).

Push button switch 24 (FIG. 4) when actuated supplies a reverse currentto jack 22 through a current limiting resister R8 in circuit 60 (FIG. 4)for reverse biasing the external solenoid diode (not shown) during adiode test. Light emitting diode 25 illuminates indicating the externalsolenoid diode is properly functioning during the diode test. When thesolenoid reverse biases, it will act as a shunt around the solenoidallowing resistor R8 in circuit 60 (FIG. 4) and resistor R6 to form avoltage divider circuit at jack 21. Transistor Q1 is then turned onallowing current to flow through light emitting diode 25 via currentlimiting resistor R1 at the collector of transistor Q1. Resistors R2 andR3 form a voltage divider circuit to the base of transistor Q1. If theexternal solenoid diode is missing or open then the voltage will dropacross the solenoid preventing Q1 from turning on. Accordingly, lightemitting diode 25 will remain off. In the exemplary embodiment, resistorR1 is a 1K ohm resistor.

FIG. 4 illustrates the electronic circuitry 60 for performing themodulated/duty-cycle solenoid test. Switch 29 turns on the electricalcircuity of circuit 60. Switch 29 receives 12 Volts from circuit 50.Push button switch 24 (as shown) connects jack 22 to ground throughcurrent limiting resistor R7. Selector switch 27 is also connected toground through current limiting resistor R7. Additionally, voltmeter 20is connected to ground through resistor R7 and to jack 23. Thus, theduty-cycle pairings are negative 22, positive 23 (the on/off solenoidand diode test pairings are negative 22, positive 21). Switch 29 isconnected to potentiometer 31 which is connected in series with resistorR10. Potentiometer 31 has a range from 0 to 5 volts. Resistor R10 isconnected in series with potentiometer 28 which is connected in serieswith one terminal of resistor R12 to form a variable control voltagefeed to one half of integrated circuit (IC) Chip 62. Potentiometer 28has a range from 0 to 5 volts. The other terminal of resistor R12 isconnected to ground. In the exemplary embodiment, resistor R7 is a 2 ohm10 Watt resistor. Potentiometers 28 and 31 are 500 ohm and 5K ohmpotentiometers, respectively. Resistors R10 and R12 are 470 ohm and 300ohm resistors, respectively.

Jack 23 is connected to the anode of light emitting diode 30 and thecathode of diode DS4. The cathode of light emitting diode 30 isconnected to ground through resistor R9 used for current limiting and tothe cathode of diode DS4. The anode of diode DS4 is connected to ground.Diode DS4 is provides a reverse current drain for the protection ofelectronic components in circuit 60. Jack 23 is further connected topolyswitch 61, shown as not connected (N/C), to protect the circuit 60from overheating due to over current conditions and prevent lightemitting diode 30 from illuminating. Polyswitch 61 is normally closedand will open upon overheating. Upon cooling, polyswitch 61automatically resets. In the exemplary embodiment, diode DS4 is a 1N5822diode.

Circuit 60 further comprises integrated (IC) chip 62 which is a LM556dual timer having first and second stage timers, U1A and U1B, whereby inoperation together provides an oscillating output to jack 23. IC chip 62is supplied a positive 12 volt VCC to pin 14 of U1B. Pin 7 of U1Aconnects to a negative voltage or ground. Reset pins 10 and 4 areconnected to a positive 12 volt VCC in order to keep IC chip 62consistently active. Output pin 9 of U1B supplies U1A with a trigger atpin 6 and is connected to VCC through resistor R5. Control pin 11 of U1Bis connected to ground through capacitor C4. Trigger and threshold pins8 and 12, respectively, of U1B are connected to ground through capacitorC7 which are in turn connected to one terminal of resistor R14 andcapacitor C8. The other terminal of capacitor C8 is connected to pin 8of selector switch 27. The other terminal of resistor R14 is connectedto discharge pin 13 of U1B. Resistor R14 and discharge pin 13 areconnected to one terminal of resistor R15. The other terminal of R15connects to two capacitors C3 with its other terminal at ground, C2 withits other terminal at ground, and R11 with its other terminal at 12 voltVSW source from push button 29. Resistors R15 and R11 and capacitors C2and C3 function as a filter circuit. In the exemplary embodiment,capacitors C2, C3, C4, C7 and C8 are 10 microfarad, 1.5 microfarad, 0.01microfarad, 0.22 microfarad and 1.5 microfarad capacitors, respectively.Resistors R5, R11, R13 and R15 are 4.7K ohm, 10 ohm, 2.2K ohm, and 23.2Kohm resistors, respectively.

The second stage timer U1A of IC chip 62 has threshold pin 2 anddischarge pin 1 connected together. Pins 1 and 2 of U1A are furtherconnected to ground through capacitor C5. Additionally, pins 1 and 2 areconnected to one side of capacitor C6. One side of resistor R16 isconnected to VCC and the other side is connected to pins 1 and 2 of U1Aand said one side of capacitor C6. The other terminal of capacitor C6 isconnected to pin 2 of selector switch 27. Control pin 3 of U1A isconnected to potentiometer 28. The output of the dual timer IC chip 62is supplied to output pin 5 of U1A. Output pin 5 is connected to thebase of transistor Q2 via resistor R4. Transistor Q2 operates to turn onand off MOSFET Q3. The collector of transmitter Q2 is connected to thegate of MOSFET Q3 and the emitter of transmitter Q2 is connected toground. MOSFET Q3 provides electronic power to jack 23. The gate ofMOSFET Q3 is also connected to one terminal of resistor R13. The otherterminal of R13 is connected to +12 volts VSW at switch 29. MOSFET Q3has its drain connected to +12 VSW and one terminal of capacitor C1. Theother terminal of capacitor C1 is connected to ground. MOSFET Q3 has itssource connected to polyswitch 61 for supplying power to jack 23.Selector switch 27 adds capacitor C8 to the discharge circuit of U1B andadds C6 to the discharge circuit of U1A for increasing or decreasing theoutput of U1A resulting in the increases or decrease of the Hertzavailable at jack 23. Selector switch 27 comprises 14 pins, pins 1 and 7are high settings; and, pins 2 and 8 are low settings. Pin 14 isconnected to ground and to pin 9 of selector switch 27. Pin 13 isconnected to ground and pin 3 of selector switch 27. In the exemplaryembodiment, transistor Q2 is a 2N3904 transistor. MOSFET Q3 is a IRF954MOSFET. Capacitors C1, C5, C6, and C8 are 47 microfarad, 0.047microfarad, 0.33 microfarad and 1.5 microfarad capacitors, respectively.Resistors R4, R13 and R16 are 4.7K ohm, 2.2K ohm and 64.9K ohmresistors, respectively. When the high and low settings are grounded,capacitance is added to the circuit by C₆ and C₈, resulting in loweringof the frequency.

The following description will be referring to the pneumatic connectionto the solenoid under test and the on/off and modulated/duty-cycledtesting procedures for operation of the present invention 10. Theoperator of the present invention 10 may bench test the solenoid whilethe solenoid is removed from the vehicle by connecting the power plug 55to any 12-Volt direct current source capable of delivering at least five(5) amperes of electrical power. On the other hand, when testing thesolenoid in the vehicle the operator may connect the present invention10 to the vehicle's cigarette lighter.

Before performing the on/off or modulated/duty-cycled testing, apparatus10 is pneumatically connected to the solenoid. When pneumaticallyconnecting the apparatus to the solenoid, air control valve 13 should beclosed by turning the valve arm down until it is horizontal or parallelto the faceplate 15. After closing air control valve 13, regulated airsupply can be connected to port 14. The air supply to nozzle 12 is thenadjusted to 30 psi for the on/off test and 50 psi for themodulated/duty-cycled test. The corresponding leads should be applied tojacks 21 and 22 for the on/off test and jacks 22 and 23 for themodulated/duty-cycled test. If a solenoid has only one wire, jack 22 canbe connected to the solenoid's metal case by conventional means.

For connecting to an on/off solenoid, the solenoid is to be placed ontothe rubber nozzle 12 by aligning the solenoid hole directly over thehole in the nozzle 12. Once the solenoid is secured in place, valve 13is moved perpendicular to the faceplate, thereby allowing air to flowinto the solenoid under test.

When performing the modulated/duty-cycled test, a separately suppliedmanifold is required. The separately supplied manifold is then connectedto port 14 using a standard female quick disconnect air fitting providedon the separately supplied manifold. The separately supplied manifoldmay require the solenoid be energized prior to providing any airpressure to the solenoid. The solenoid is secured to the separatelysupplied manifold via a F-clamp.

Upon completion of the pneumatic connection, as described above, theon/off testing is performed by actuating switch 26 thereby energizingthe solenoid under test. The circuitry is designed to limit amperage to1.6 amps. As the air pressure flows through the intake port of thesolenoid, the operator will observe changes in air pressure on thepressure gauge 11. Specifically, a slight drop in pressure will be seenas the pressure flows through the intake port of the solenoid indicatingthe solenoid is functioning properly. On the other hand, if the pressuredoes not drop the solenoid has failed to open thereby indicating afaulty solenoid. For open type solenoids, a slight rise in pressure willbe seen. Henceforth, the pneumatic integrity of the solenoid has beendetermined. The pneumatic operation of the solenoid may be furtherdetermined by deenergizing the solenoid and monitoring the air flowthrough valve 13. In further operation, light emitting diode 25 willilluminate if the solenoid is functioning properly; otherwise, lightemitting diode 25 will remain off if the solenoid is electrically faultywhereby the electrical integrity of the solenoid has been determined.

Upon completion of the on/off solenoid test, a diode test is performedon an external solenoid diode, of a 15 ohm or higher solenoid, byactuating switch 24. Light emitting diode 25 will illuminate if theexternal solenoid diode is functioning properly. On the other hand,light emitting diode 25 will remain off if the external solenoid diodeis missing or faulty.

Alternately, upon completion of the pneumatic connection, as describedabove, the modulated/duty-cycled test may be performed. The selectorswitch 27 should be set on high or low in accordance with Table 1 setforth below.

                  TABLE 1                                                         ______________________________________                                        Setting   Hertz           Solenoid                                            ______________________________________                                        HIGH      220 cycles per second                                                                         Pressure control                                    (U.S.)                                                                        LOW        30 cycles per second                                                                         Modulated converter                                                           clutch (U.S.)                                       LOW        30 cycles per second                                                                         Pressure control                                                              (Asian)                                             ______________________________________                                    

Switch 29 is then actuated to turned on circuitry 60. Potentiometer 28is manipulated to calibrate voltmeter (20) to 5 volts when the selectorswitch 27 is set on HIGH. If selector switch 27 is set on LOW,potentiometer 28 is manipulated to calibrate voltmeter (20) inaccordance with the highest voltage specified for the solenoid. Finally,potentiometer 31 is manipulated to set the duty cycle voltage to thelowest voltage specified for a solenoid.

Since describing the test procedures for all solenoids that the presentinvention 10 is applicable to is prohibitive, a description of theprocedure for testing a MCC-4L80E solenoid is provided below. Selectorswitch 27 is set on LOW and switch 29 is actuated to supply power to thecircuitry 60. Potentiometer 28 is manipulated to calibrate the voltmeter(20) to 5 volts, the highest specified voltage. Potentiometer 31 ismanipulated to 1 volt by observing the voltage drop on Voltmeter (20).While manipulating the potentiometer 31 to 1 volt, a corresponding dropin air pressure as seen on pressure gauge 11 should be observed. Thedrop in air pressure will be in the range of 40 psi to 0 psi.

Because many varying and differing embodiments may be made within thescope of the inventive concept herein taught and because manymodifications may be made in the embodiment herein detailed inaccordance with the descriptive requirement of the law, it is to beunderstood that the details herein are to be interpreted as illustrativeand not in a limiting sense.

What is claimed as invention is:
 1. An apparatus having first and secondtest modes for testing a solenoid in a computer controlled transmissioncomprising:(a) first connection means for connecting a first test modecircuit means to a positive side of the solenoid for said first testmode when the solenoid is of a first mode of operation; (b) secondconnection means for connecting said first test mode circuit means and asecond test mode circuit means to a negative side of the solenoid forsaid first test mode when the solenoid is of said first test mode ofoperation or for said second test mode when the solenoid is of a secondmode of operation, wherein said first and second test modes are variablevoltage and modulated/duty-cycled, respectively; (c) third connectionmeans for connecting said second test mode circuit means to the positiveside of the solenoid for said second test mode when the solenoid is ofsaid second mode of operation; and, (d) switch means coupled to thesecond connection means wherein actuation of said switch means initiatesa diode test through said second connection means to said firstconnection means.
 2. The apparatus of claim 1, wherein said second testmode circuit means for performing said second test mode comprises:(a)first switch means for providing power; control means coupled to saidfirst switch means for controlling a duty-cycle output to said thirdconnection means; (b) range adjustment control means coupled to saidcontrol means for setting a voltage; and, (c) dual timer means coupledto said range adjustment control means for providing an oscillatingoutput to said third connection means; (d) selecting means coupled tosaid dual timer means for selecting a frequency; and, (e) meter meanscoupled to said third connection means and said switch means forindicating a voltage drop.
 3. The apparatus of claim 2, wherein saidsecond test mode circuit means further comprises protection meanscoupled to said dual timer means and said third connection means forproviding overheating protection.
 4. The apparatus of claim 2, whereinsaid dual timer means comprises a first stage and a second stage whereinsaid first stage is coupled to a filter means, the second stage of saiddual timer means and to said selecting means; and said second stage ofsaid dual timer means is coupled to said range adjustment control meansand said selecting means.
 5. The apparatus of claim 1, wherein saidfirst test mode circuit means for performing said first test modecomprises:(a) switch means coupled to said first connection means forproviding power to the solenoid; and, (b) indicator means coupled tosaid first connection means for indicating the operation of thesolenoid.
 6. The apparatus of claim 5, further comprises protectionmeans coupled to said switch means of said first test mode circuit meansfor providing over current and over voltage protection.
 7. The apparatusof claim 1, further comprising pneumatic means wherein said pneumaticmeans comprising:(a) port means for receiving air pressure; (b) nozzlemeans coupled to said port means for providing said air pressure to thesolenoid; (c) control valve coupled to said nozzle means for controllingsaid air pressure from said nozzle to the solenoid; and, (d) pressuregauge means for indicating air pressure flowing through the solenoid.